The present disclosure relates to shaft seals for gas turbine engines, and more specifically to seals between a low rotor shaft and a high rotor shaft in a gas turbine engine.
Secondary flow systems in gas turbine engines direct cooling air to various locations in the gas turbine engine to keep engine components from overheating. In some gas turbine engines, the secondary flow system will direct cooling air across the high rotor shaft and into the low rotor shaft to deliver cooling air to the turbine section of the engine. In these gas turbine engines, seals are required between the high rotor shaft and the low rotor shaft to keep higher-pressure higher-temperature gases from leaking into the secondary flow systems.
Traditionally, knife edge seals have been used between the high rotor shaft and the low rotor shaft to reduce leakage. However, knife edge seals, to be affective at controlling leakage, require relatively small deflections between the low rotor shaft and the high rotor shaft. If deflections are relatively large between the low rotor shaft and the high rotor shaft, additional bearing assemblies within the gas turbine engine may be required, which increases the cost, complexity, and overall weight of the gas turbine engine.